The major aim of this ACTG study is to longitudinally follow infants, children, and adolescents who have participated in perinatal and pediatric ACTG clinical trials in order to monitor late consequences of therapy including long-term survival and quality of life. A secondary aim of the late outcomes protocol will be to provide data describing the demographic, medical and treatment characteristics of children enrolled in ACTG clinical trials and children at ACTG sites enrolled in the Long Term Survivors study sponsored by the Pediatric AIDS Foundation, and which track improvements in survival and quality of life of successive cohorts over time.